1. Field of the Invention
The invention relates generally to the field of surgical instruments, and more particularly, to surgical retractors.
2. Brief Description of the Prior Art
Surgical retractors are medical instruments which hold a patient's tissue such that the edges of a surgical incision are away from the field of surgery. Surgical retractors typically have retractor arms attached to a support shaft. The retractor arms are positioned within the surgical incision and then spread to allow an open field of surgery. An example of a prior art surgical retractor is given in Koros, et al., U.S. Pat. No. 5,167,223, which is incorporated herein by reference.
In cardiopulmonary bypass surgery (CPB) surgery, the patient's sternum is spread using a surgical retractor. This allows the surgeon access to the patient's heart to perform the necessary procedures. Typically a cannula is inserted within the patient's right atrium to withdraw blood from the patient's heart, a second cannula is placed within the patient's aorta to return blood to the patient. The cannula are connected to a blood pump which is usually placed outside the surgical field, and is connected to the patient with tubing. During surgical procedures the surgeon must insure that the cannula are not disturbed from their placement. Typically when inserting the cannula the surgeon inserts a purse string incision at the target location, inserts the cannula then pulls the purse string tight, thereby creating a seal about the diameter of the cannula. If the cannula moves or deflects to a certain degree the purse string may leak if this happens the surgeon must tighten the purse string more to eliminate the leak, it is possible that the leak may not be stoppable and the cannula must be reinserted through a new purse string at another location and the first purse string must be sutured closed. Also during bypass procedures the venous drainage line is placed within the patient's right atrium. This line drains blood from the body by gravity, therefore this line is very sensitive to placement within the atrium and any movement during the surgical procedure. This tends to complicate the surgical procedure and increase the amount of time that the patient is on the CPB circuit Additionally, movement of any of the cannula that cause the openings to become occluded results in a reduced flow rate through the CPB circuit which may cause complications in the surgical procedure.
Open heart surgery is delicate work in which the blood flow must be maintained while the procedure is performed by the surgeon on fragile blood vessels. It is desired to have an improved surgical retractor that can aid in performing this delicate work.